Ender 3 V2: Inject 'G28 O' before G29 (#18767)

Marlin/src/lcd/dwin/dwin.cpp

 void HMI_Leveling(void) {
   Popup_Window_Leveling();
   DWIN_UpdateLCD();
-  queue.inject_P(PSTR("G29"));
+  queue.inject_P(PSTR("G28O\nG29"));
 }
 
 /* Axis Move */